Piecemeal Group Research Articles

CLRM-03 THE TENTATIVE APPLICATION OF EN BLOC CONCEPT IN THE PEDIATRIC BRAIN TUMOR: EXPERIENCE FROM A LARGE PEDIATRIC CENTER IN CHINA

Abstract BACKGROUND The less allowable blood loss and tolerance of intraoperative blood loss of children lead to the high rate of massive blood transfusion. The surgical concepts of en bloc resection may contribute to the improvement of brain tumor resection. OBJECTIVE To investigate the effects of en bloc concept on short outcomes of pediatric brain tumors and factors associated with the application of en bloc concept. METHODS According to the surgical concept involved, the patients were divided into three subgroups-complete en bloc concept, partial en bloc concept and piecemeal concept. The matching-comparison(en bloc group consisting of the first two subgroups and piecemeal group) was conducted to investigate the effect of the en bloc concept on the short-term outcomes. Then the patient data after January 2018, when the en bloc concept was routinely integrated into brain tumor surgery in our medical center, were reviewed and analyzed to find out the predictors associated with the application of en bloc concept. RESULTS In the en bloc group, the perioperative outcomes, including hospital stay(p=0.001), PICU stay(p=0.003), total blood loss(p=0.015), transfusion rate(p=0.005) and complication rate(p=0.039), were all significantly improved. The multinomial logistic regression analysis showed that tumor volume, bottom vessel, and imaging features, like encasing nerve or pass-by vessel, finger-like attachment, ratio of “limited line” and ratio of “clear line” remained independent predictors for the application of en bloc concept in our medical center. CONCLUSION The application of en bloc concept based on the imaging features can improve the short-term outcomes.

Surface Electromyography for Evaluating the Effect of Aging on the Coordination of Swallowing Muscles

Swallowing function can deteriorate with age, leading to a risk of dysphagia. Swallowing evaluation by surface electromyography (sEMG) can be easily and extensively applied for an elderly population. This study evaluated the temporal events observed by sEMG to clarify how aging affects the coordination among the masticatory and suprahyoid muscles. We recruited elderly individuals (over 65 years old) who denied dysphagia. The sEMG activities of anterior temporalis, masseter, and suprahyoid muscles were recorded during 3, 15, and 30 ml water swallowing tests (WST). We calculated the time interval between anterior temporalis and suprahyoid peak activity (T-SH interval) and masseter and suprahyoid peak activity (M-SH interval) and analyzed their correlation with age. The subjects who could and could not swallow 30 ml of water in one gulp were further assigned into the one-gulp and piecemeal groups, respectively, for subgroup analysis. We recruited 101 subjects, among whom 75 (26 males and 49 females) were analyzed after excluding those with suspected dysphagia or low-quality sEMG recordings. Age was significantly correlated with the bilateral T-SH (left: r = 0.249, p = 0.031; right: r = 0.412, p < 0.01) and right M-SH (r = 0.242, p = 0.037) intervals in the 30 ml WST. The correlation between intervals and age were observed in both subgroups. sEMG can be used to investigate the effect of aging on the temporal coordination between masticatory and suprahyoid contraction. Further studies are needed to verify the validity of screening subclinical dysphagia in the elderly.

SURG-01. The Tentative Application of En Bloc concept in the Pediatric Brain Tumor: A Retrospective Study of 171 Cases from A Large Pediatric Center in China

BACKGROUND: The less allowable blood loss and tolerance of intraoperative blood loss of children lead to the high rate of massive blood transfusion. The surgical concepts of en bloc resection may contribute to the improvement of brain tumor resection. OBJECTIVE: To investigate the effects of en bloc concept on short outcomes of pediatric brain tumors and factors associated with the application of en bloc concept. METHODS: According to the surgical concept involved, the patients were divided into three subgroups-complete en bloc concept, partial en bloc concept and piecemeal concept. The matching-comparison(en bloc group consisting of the first two subgroups and piecemeal group) was conducted to investigate the effect of the en bloc concept on the short-term outcomes. Then the patient data after January 2018, when the en bloc concept was routinely integrated into brain tumor surgery in our medical center, were reviewed and analyzed to find out the predictors associated with the application of en bloc concept. RESULTS: In the en bloc group, the perioperative outcomes, including hospital stay(p=0.001), PICU stay(p=0.003), total blood loss(p=0.015), transfusion rate(p=0.005) and complication rate(p=0.039), were all significantly improved. The multinomial logistic regression analysis showed that tumor volume, bottom vessel, and imaging features, like encasing nerve or pass-by vessel, finger-like attachment, ratio of “limited line” and ratio of “clear line” remained independent predictors for the application of en bloc concept in our medical center. CONCLUSION: The application of en bloc concept based on the imaging features can improve the short-term outcomes.

SURG-13. THE TENTATIVE APPLICATION OF EN BLOC CONCEPT IN THE PEDIATRIC BRAIN TUMOR: EXPERIENCE FROM A LARGE PEDIATRIC CENTER IN CHINA

Abstract BACKGROUND The less allowable blood loss and tolerance of intraoperative blood loss of children lead to the high rate of massive blood transfusion. The surgical concepts of en bloc resection may contribute to the improvement of brain tumor resection. OBJECTIVE To investigate the effects of en bloc concept on short outcomes of pediatric brain tumors and factors associated with the application of en bloc concept. METHODS According to the surgical concept involved, the patients were divided into three subgroups-complete en bloc concept, partial en bloc concept and piecemeal concept. The matching-comparison(en bloc group consisting of the first two subgroups and piecemeal group) was conducted to investigate the effect of the en bloc concept on the short-term outcomes. Then the patient data after January 2018, when the en bloc concept was routinely integrated into brain tumor surgery in our medical center, were reviewed and analyzed to find out the predictors associated with the application of en bloc concept. RESULTS In the en bloc group, the perioperative outcomes, including hospital stay(p=0.001), PICU stay(p=0.003), total blood loss(p=0.015), transfusion rate(p=0.005) and complication rate(p=0.039), were all significantly improved. The multinomial logistic regression analysis showed that tumor volume, bottom vessel, and imaging features, like encasing nerve or pass-by vessel, finger-like attachment, ratio of “limited line” and ratio of “clear line” remained independent predictors for the application of en bloc concept in our medical center.

EMBR-05. THE TENTATIVE APPLICATION OF EN BLOC CONCEPT IN THE PEDIATRIC BRAIN TUMOR: EXPERIENCE FROM A LARGE PEDIATRIC CENTER IN CHINA

BackgroundThe less allowable blood loss and tolerance of intraoperative blood loss of children lead to the high rate of massive blood transfusion in the treatment of brain tumor. The surgical concepts of en bloc resection may contribute to the improvement of brain tumor resection. ObjectiveTo investigate the effects of en bloc concept on short outcomes of pediatric brain tumors and factors associated with the application of en bloc concept. MethodsAccording to the surgical concept involved, the patients were divided into three subgroups-complete en bloc concept, partial en bloc concept and piecemeal concept. The matching-comparison (piecemeal group and en bloc group formed from the first two subgroups) was conducted based on age, tumor location, lesion volume, and pathological diagnosis to investigate effect of the en bloc concept on the short-term outcomes. Then the patient data after January 2018, when the en bloc concept was routinely integrated into brain tumor surgery in our medical center, were reviewed and analyzed to find out the predictors associated with the application of en bloc concept. ResultsIn the en bloc group, the perioperative outcomes, including hospital stay (p=0.001), PICU stay (p=0.003), total blood loss(p=0.015), transfusion rate(p=0.005) and complication rate(p=0.039), were all significantly improved. The multinomial logistic regression analysis showed that tumor volume and imaging features, like bottom vessel, encasing nerve or pass-by vessel, finger-like attachment, ratio of “limited line” and ratio of “clear line” remained independent factors for the application of en bloc concept in our medical center. ConclusionThis study supports the application of complete or partial en bloc concept in the pediatric brain tumor surgery referring to the preoperative imaging features, and compared with piecemeal concept, en bloc concept can improve the short outcomes without significant increases in neurological complication. Large series and Additional supportive evidence are still warranted.

Quantitative and qualitative analyses of spinal canal encroachment during cervical laminectomy using the kerrison rongeur versus High-Speed burr

Background: Several cervical laminectomy techniques have been described. One commonly used method involves making bilateral trough laminotomies using either a Kerrison rongeur or a high speed burr, and then removing the lamina en-bloc. Alternatively, some surgeons prefer to thin the lamina with the burr, and then remove the lamina in a piecemeal fashion using Kerrison rongeurs. Some surgeons have warned against the potential risk of iatrogenic spinal cord injury from inserting the Kerrison footplate into a stenotic canal. We aim to quantify the amount of canal encroachment for various methods of cervical laminectomies. Methods: Three attending spine surgeons and two fellows each performed laminectomies using C5 sawbones models. The canal was completely filled with modeling putty to simulate a stenotic spinal cord. Bilateral trough laminotomies were performed using a 1 mm Kerrison, a 2 mm Kerrison, and a 3 mm matchstick high-speed burr. Piecemeal laminectomies were performed with a 2 mm Kerrison. A blinded spine surgery fellow performed all quantitative measurements. Three blinded researchers qualitatively ranked the amount of “canal encroachment”. Results: The average canal encroachment was 0.50 ± 0.45mm for the burr, 1.37 ± 0.68 mm for the 1 mm Kerrison, and 1.47 ± 0.37 mm for the 2 mm Kerrison (p = .002). There was a statistically significant difference between the burr and 1 mm Kerrison (p = .01) and between the burr and the 2 mm Kerrison (p = .001). There was no statistical difference between the 1 mm and 2 mm Kerrison (p = .78). The mean rank of the burr group, the Kerrison rongeur group, and the piecemeal group were 1.41, 1.94, and 2.65, respectively, on an ordinal scale of 1–3. Conclusion: When performing a trough laminotomy, the high-speed burr results in less canal encroachment compared to 1 mm or 2 mm Kerrison rongeurs. In the setting of a stenotic spinal canal, spine surgeons should consider using the burr to perform laminectomy to minimize the degree of canal encroachment.

Risk for local recurrence of early gastric cancer treated with piecemeal endoscopic mucosal resection during a 10-year follow-up period

Endoscopic mucosal resection (EMR) is a therapy for early gastric cancer (EGC) that can be provided relatively easily and safely in any institution. Identification of the resection margin is a problem in EMR, especially in cases of piecemeal EMR. Despite the long-standing widespread use of piecemeal EMR for EGC, its limitation and long-term outcomes in clinical practice have not been fully evaluated. This study aimed to determine the risk factors of piecemeal EMR, the local recurrence rates, and the mortality rate. A cross-sectional, retrospective cohort study was performed to investigate the risks of piecemeal EMR for patients with the diagnosis of differentiated adenocarcinoma localized to the mucosa. Local recurrence of EGC was investigated by annual follow-up esophagogastroduodenoscopy (EGD) for 10years. EMR was performed with snare electrocautery using a two-channel scope. When a resection margin was clearly positive for cancer, additional surgery was performed soon after the initial EMR. For the 149 EGC patients (mean age, 68.8±9.8; male, 77%) who underwent EMR between 1995 and 2001, EMR was performed en bloc in 66 cases and piecemeal in 83 cases. The comorbid conditions existing in 34 of the 149 patients included other malignancies (n=12), heart failure (n=5), pulmonary disease (n=7), liver cirrhosis (n=4), and other illness (n=6). However, EMR was completed without complication. The mean area (length×width) of the lesions was 404±289mm(2) in the piecemeal group and 250±138mm(2) in the en bloc groups. The en bloc and piecemeal EMR groups differed significantly in terms of unclear horizontal margins but not in terms of unclear vertical margins. Multiple logistic regression suggested that the adjusted odds ratio for maximum diameters exceeding 20mm for piecemeal EMR was 2.71 (95% confidence interval [CI], 1.30-5.64). According to Kaplan-Meier estimates, the local recurrence rate was 30% (95% CI, 20-40%) at both 5 and 10years. No recurrence was observed in the en bloc group. The adjusted hazard ratio of unclear horizontal margins for local recurrence was 1.63 (95% CI, 1.12-2.36). A total of 24 patients died after EMR because of comorbid conditions, including other malignancies (n=11), cardiovascular disease (n=6), pulmonary disease (n=4), liver cirrhosis (n=2), and traffic accident (n=1). However, no patient died of gastric cancer during the 10-year follow-up period. An evaluation of horizontal margins in terms of local recurrence after piecemeal EMR is important, and en bloc resection is recommended. Close follow-up assessment is warranted, especially within 5years in cases of unclear margin resection after piecemeal EMR. The use of EMR is safe even for patients with severe comorbid conditions.

Polyp Recurrence After Endoscopic Mucosal Resection of Sessile and Flat Colonic Adenomas

Endoscopic mucosal resection (EMR) is used for treatment of sessile and flat colonic adenomas. There is limited data comparing polyp recurrence between piecemeal and en-bloc resections. The purpose of this study was to evaluate the incidence density and predictive factors for polyp recurrence after piecemeal and en-bloc resections. Patients undergoing EMR of flat or sessile adenomas≥10 mm were included. Incidence density (ID) and incidence rate ratio (IRR) of polyp recurrence were calculated. Predictive factors for recurrence were assessed by multivariate analysis using logistic regression. A total of 105 patients (males 54, mean age 68) with 121 polyps were included. Sixty-seven polyps (mean size±SD, 23.3±9.2 mm) were resected piecemeal and 54 polyps (mean size 14.7±5.1 mm) were resected en-bloc. There were 12 recurrences in the piecemeal group and two in the en-bloc group. The ID of polyp recurrence in the piecemeal group was 13.1 (95% CI 7.43-23.03) and in the en-bloc group was 2.7 (95% CI 0.67-10.78) per 100 person-years of follow-up. Piecemeal resections were 5.5 (95% CI 1.1-30.48, P=0.045) times and flat polyps were 6.6 (95% CI 1.22-35.53, P=0.028) times more likely to result in recurrence compared to en-bloc resections and sessile polyps, respectively. In the piecemeal group, additional use of argon plasma coagulation (APC) did not affect the recurrence (OR 0.46, P=0.29). Piecemeal resections and flat polyps are associated with higher recurrence following EMR. Additional use of APC did not affect the recurrence rates after piecemeal resection.

PTU-015 Incidence of polyp recurrence after endoscopic mucosal resection of flat and sessile colonic polyps

<h3>Introduction</h3> Endoscopic mucosal resection (EMR) is now widely used for treatment of sessile and flat colonic adenomas. En-bloc resection is believed to have many theoretical advantages including better histological assessment and lower recurrence rates. There are limited data directly comparing the polyp recurrence rates following endoscopically complete resection by either piecemeal or en-bloc resection techniques. <h3>Methods</h3> The aim of the study was to evaluate the incidence density (polyp recurrence) after piecemeal or en-bloc resection and to calculate the adjusted incidence rate ratio between these two methods. All patients undergoing EMR of flat or sessile colonic polyps &gt;10 mm were prospectively audited in a single tertiary centre hospital. Duration of follow-up was calculated from the time of EMR to the date of the last follow-up colonoscopy. Follow-up colonoscopies were determined by the British Society of Gastroenterology guidelines. Incidence density of polyp recurrence was calculated in patients undergoing either piecemeal or en-bloc resection and a Poisson distribution was assumed for the purposes of calculation. Analysis for incidence rate ratio was adjusted for the site and size of lesion, use of argon plasma coagulation (APC), morphology of the lesion and histology of lesion. Stata V.9.1 was used for the analysis. <h3>Results</h3> EMR was performed on 154 polyps &gt;10 mm in size in 130 patients (69 males, mean age 68). 79 polyps with a mean size of 22.6±9 mm were resected piecemeal and 75 polyps with a mean size of 14.6±5.5 mm were resected en-bloc. There were nine recurrences in the piecemeal group and one recurrence in the en-bloc group. The incidence density (ID) of polyp recurrence in the piecemeal group was 80.2 per 1000 person years of follow-up (95% CI 36.7 to 152.2). The ID of polyp recurrence in the en-bloc group was 10.7 per 1000 person years of follow-up (95% CI 0.3 to 59.6). The adjusted incidence rate ratio (IRR) for recurrence in the en-bloc compared to piecemeal group was 0.42 (95% CI 0.22 to 0.78). Among patients undergoing piecemeal resection, the adjusted IRR for additional use of APC was 0.7 (95% CI 0.38 to 1.27), for histologically less advanced lesions was 0.3 (95% CI 0.14 to 0.61) and for sessile but not flat lesions was 0.13 (95% CI 0.19 to 0.75). <h3>Conclusion</h3> The adjusted recurrence rates after en-bloc resection of colonic polyps are 60% less than that after piecemeal resection. The use of APC did not significantly change the recurrence rates after piecemeal resection, but flat lesions and histologically advanced lesions made recurrences more likely.

Local recurrence after endoscopic resection of colorectal tumors

Local recurrence frequently occurs after endoscopic resection of large colorectal tumors. However, appropriate intervals for surveillance colonoscopy to assess local recurrence after endoscopic resection have not been clarified. The aim of the present study was to determine local recurrence rates following en-bloc and piecemeal endoscopic resection and establish appropriate surveillance colonoscopy intervals based on retrospective analysis of local recurrences. A total of 461 patients with 572 > or = 10-mm lesions underwent endoscopic resection and follow-up. We retrospectively compared local recurrence rates on lesion size, macroscopic type, and histological type after en-bloc resection (440 lesions) and piecemeal resection (132 lesions). Cumulative local recurrence rates were analyzed using the Kaplan-Meier method. Local recurrence occurred for 34 lesions (5.9%). Local recurrence rates for the en-bloc and piecemeal groups was 0.7% (3/440) and 23.5% (31/132), respectively (P < 0.001). The difference between the two groups was distinct in terms of lesion size, macroscopic type, and histological type. Of the 34 local recurrences, 32 were treated endoscopically and two cases required additional surgery. The 6-, 12-, and 24-month cumulative local recurrence rate of the en-bloc group was 0.24%, 0.49%, and 0.81%. Then the 6-, 12-, and 24-month cumulative local recurrence rate for the piecemeal group was 18.4%, 23.1%, and 30.7%. Local recurrence occurred more frequently after piecemeal resection than en-bloc resection. However, almost all cases of local recurrences could be cured by additional endoscopic resection, so piecemeal resection can be acceptable treatment.

EMR of Large Sessile Colorectal Polyps: Are Complications and Recurrences Related to the Technique?

BACKGROUND: Several techniques have been proposed for endoscopic mucosal resection (EMR) of large flat adenomas of the colon. AIMS: to evaluate bleeding and recurrence rates after EMR of large sessile colonic adenomas as a function of different techniques. METHODS: 65 sessile colonic adenomas larger than 2 cm were treated by EMR in 57 patients. Mean larger diameter of the polyps was 28 mm (20-80). Lesions were lifted with saline solution alone (n=26) or saline solution plus epinephrine 1:10.000 (n=39). En bloc EMR (n=29) or piecemeal EMR (n=36) were performed. APC was used when residual adenomatous tissue was recognized after EMR (n=36). Endoscopic follow-up was performed at 3, 6 and 12 months. RESULTS:. Procedural bleedings occurred in 9 EMR (13,8%): 5/26 in the saline group and 4/39 in the epinephrine group (p=ns). They were all successfully treated by APC and/or clips application. All the resected specimens were retrieved for histological examination: 22 were adenomas with LGD, 26 with HGD/in-situ carcinoma, 14 were carcinomas infiltrating the upper third of the submucosa, 3 were infiltrating deep submucosa. 13 patients (15 polyps) eventually underwent surgery: none of these patients had lymph node metastases or residual adenoma at the site of polypectomy; five patients (five polyps) were lost to follow-up. Residual adenomatous tissue or recurrences were observed at the site of 13 EMR: 8/21 in the APC group and 5/24 in the non APC group (p=ns), 5/20 in the en bloc and 8/25 in the piecemeal group (p=ns), respectively. All recurrences were endoscopically retreated (by APC or EMR) with complete eradication in 10 cases while in 3 patients treatment is still on-going. CONCLUSION: EMR for large colonic polyps is feasible and safe. Adrenaline injection did not significantly prevent bleeding; use of APC on residual adenoma and type of resection did not significantly influence the recurrence rate. Being incidence of recurrence usually high for these polyps, a close follow-up is required. Endoscopic retreatment of recurrences is able to obtain the complete eradication of the lesion.

3468 Evaluation of endoscopic mucosal resection by enbloc and by piecemeal for early gastric cancer.

Background & Aims: In Japan, EMR is generally accepted as the curative treatment for differentiated histological type mucosal cancer with minimum probability of lymph node metastasis. Although many EMR techniques are reported, a standard method has not been established. As to surgical operation, the tumor is usually removed by an en-bloc resection. In EMR, however, the piecemeal resection is often performed because of technical difficulties. To clarify whether the piecemeal resection for EGC is permited or not, we compared and evaluated clinical outcomes (curability, local recurrence) and tumor characteristics (size, location) between en-bloc and piecemeal resection. Patients: Through January 1995 and June 1999 at National Cancer Center Hospital, 402 cancers (372 patients, M/F:298/74, mean age:65.9 y) were treated by EMR according to our endoscopic applications: (1) differentiated-type adenocarcinoma by biopsy, (2) macroscopically I, IIa and IIc types and (3) absence of ulcerative and invasive findings. In the resected specimen, when the above applications including no lymph-vascular involvement and free margins are histologically confirmed, the resection was regarded as “curative”. The resected specimen with difficulty for accurate histological examination was regarded as “not evaluable”. Results: 1. Of 340 intramucosal cancers, 197 (58%) were resected by en-bloc and 143 by piecemeal, though 62 (15%) of 402 lesions invaded submusal layer. 2. Curative resection rate was 93 percent (183/197) by en-bloc and 59 (84/143) by piecemeal. Two cases developed local recurrence after piecemeal resection, but not after en-bloc resection. 3. Two (4/197) and 10 percent (14/143) was histologically not evaluable, respectively. 4. The number of tumor more than 20mm in diameter was 16 lesions (8%) in en-bloc group in contrast with 31 (22%) for piecemeal group. 5. Twenty-six lesions (13%) were located in the upper third of the stomach in en-bloc group and 29 (21%) for piecemeal group. Conclusion: The curative resection rate by en-bloc was much higher than that by piecemeal, and local recurrence rate was lower for en-bloc group. Forthermore the rate of “not evaluable” was low for en-bloc resection. These results suggest that EGC should be removed by en-bloc for curability and accurate histological examination. Therefore, development of new instrument would be needed to resect the lesions located in upper third and larger lesions by en-bloc.